Ok , so downgrade firmware - NOK
Tried with WIN 7, Win XP - NOK
Disconnected Router , connect only with Gigabit Switch - NOK
Reconfigure Router + firmware - NOK
Format disk on WD Live Hub - NOK
NOK means network speed is ~3-4 Mb , after several months worked with 15Mb/sec.
I'm out of ideas , I HATE this media player.